From: Stefano Stabellini <stefano.stabellini@amd.com>
To: <xen-devel@lists.xenproject.org>
Cc: <sstabellini@kernel.org>, <bertrand.marquis@arm.com>,
<julien@xen.org>, <michal.orzel@amd.com>,
<Volodymyr_Babchuk@epam.com>, Henry Wang <xin.wang2@amd.com>
Subject: [PATCH v5 5/9] docs/features/dom0less: Update the late XenStore init protocol
Date: Wed, 5 Feb 2025 17:08:39 -0800 [thread overview]
Message-ID: <20250206010843.618280-5-stefano.stabellini@amd.com> (raw)
In-Reply-To: <alpine.DEB.2.22.394.2502041807070.9756@ubuntu-linux-20-04-desktop>
From: Henry Wang <xin.wang2@amd.com>
With the new allocation strategy of Dom0less DomUs XenStore page,
update the doc of the late XenStore init protocol accordingly.
Signed-off-by: Henry Wang <xin.wang2@amd.com>
---
docs/features/dom0less.pandoc | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/docs/features/dom0less.pandoc b/docs/features/dom0less.pandoc
index 725afa0558..8b178edee0 100644
--- a/docs/features/dom0less.pandoc
+++ b/docs/features/dom0less.pandoc
@@ -110,9 +110,10 @@ hotplug PV drivers to dom0less guests. E.g. xl network-attach domU.
The implementation works as follows:
- Xen allocates the xenstore event channel for each dom0less domU that
has the "xen,enhanced" property, and sets HVM_PARAM_STORE_EVTCHN
-- Xen does *not* allocate the xenstore page and sets HVM_PARAM_STORE_PFN
- to ~0ULL (invalid)
-- Dom0less domU kernels check that HVM_PARAM_STORE_PFN is set to invalid
+- Xen allocates the xenstore page and sets HVM_PARAM_STORE_PFN as well
+ as the connection status to XENSTORE_RECONNECT.
+- Dom0less domU kernels check that HVM_PARAM_STORE_PFN is set to
+ ~0ULL (invalid) or the connection status is *not* XENSTORE_CONNECTED.
- Old kernels will continue without xenstore support (Note: some old
buggy kernels might crash because they don't check the validity of
HVM_PARAM_STORE_PFN before using it! Disable "xen,enhanced" in
@@ -121,13 +122,14 @@ The implementation works as follows:
channel (HVM_PARAM_STORE_EVTCHN) before continuing with the
initialization
- Once dom0 is booted, init-dom0less is executed:
- - it allocates the xenstore shared page and sets HVM_PARAM_STORE_PFN
+ - it gets the xenstore shared page from HVM_PARAM_STORE_PFN
- it calls xs_introduce_domain
- Xenstored notices the new domain, initializes interfaces as usual, and
sends an event channel notification to the domain using the xenstore
event channel (HVM_PARAM_STORE_EVTCHN)
- The Linux domU kernel receives the event channel notification, checks
- HVM_PARAM_STORE_PFN again and continue with the initialization
+ HVM_PARAM_STORE_PFN and the connection status again and continue with
+ the initialization
Limitations
--
2.25.1
next prev parent reply other threads:[~2025-02-06 1:09 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-06 1:08 [PATCH v5 0/9] Guest XenStore page allocation for 11 Dom0less domUs Stefano Stabellini
2025-02-06 1:08 ` [PATCH v5 1/9] automation: upgrade Linux kernel for arm64 tests to 6.6.74 Stefano Stabellini
2025-02-06 7:58 ` Orzel, Michal
2025-02-06 23:12 ` Stefano Stabellini
2025-02-06 1:08 ` [PATCH v5 2/9] xen/arm/static-shmem: Static-shmem should be direct-mapped for direct-mapped domains Stefano Stabellini
2025-02-06 8:04 ` Orzel, Michal
2025-02-06 23:13 ` Stefano Stabellini
2025-02-06 1:08 ` [PATCH v5 3/9] xen/arm: Alloc XenStore page for Dom0less DomUs from hypervisor Stefano Stabellini
2025-02-06 10:20 ` Orzel, Michal
2025-02-07 1:19 ` Stefano Stabellini
2025-02-06 1:08 ` [PATCH v5 4/9] tools/init-dom0less: Avoid hardcoding GUEST_MAGIC_BASE Stefano Stabellini
2025-02-06 1:08 ` Stefano Stabellini [this message]
2025-02-06 1:08 ` [PATCH v5 6/9] automation: add ping test to static-mem test Stefano Stabellini
2025-02-06 1:08 ` [PATCH v5 7/9] init-dom0less: allocate xenstore page is not already allocated Stefano Stabellini
2025-02-06 12:37 ` Jan Beulich
2025-02-06 23:14 ` Stefano Stabellini
2025-02-06 1:08 ` [PATCH v5 8/9] xen/arm: introduce legacy dom0less option for xenstore allocation Stefano Stabellini
2025-02-06 12:08 ` Orzel, Michal
2025-02-07 1:43 ` Stefano Stabellini
2025-02-06 1:08 ` [PATCH v5 9/9] [DO NOT COMMIT] automation: add one test using an older unpatched Linux kernel Stefano Stabellini
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